1. Field of the Invention
The present invention relates to a starting device of an engine for causing a starter motor to rotate an engine starting shaft through a starter clutch.
2. Description of the Related Art
A general starting device of an engine is provided with a starter gear rotated by a starter motor, a rotor of a generator connected to a crankshaft, and a starter clutch for transmitting rotary motion from the starter gear only to the rotor. The starter clutch has an outer race fixed to the rotor for rotation therewith and a cam interposed between the outer race and the starter gear.
In the generator, a cooling hole is defined for allowing air or cooling engine oil to pass therethrough after having cooled a stator coil disposed facing the rotor to thereby cool the stator coil (see JP-A-2001-45686 (Patent Document 1), for example).
In the conventional starting device, when an outer race of the starter clutch has an insufficient rigidity, the outer race may be deformed, which may result in slippage of the cam in some cases. This interferes with smooth starting of the engine.
For additional rigidity, increasing the outer race in a radial dimension is conceivable. However, when the outer race is increased simply in the radial dimension, the outer race may block the cooling hole in the rotor. This causes a problem of degradation in the cooling capability of the stator coil.